Wildlife Trader Spread Virus Over Thousands of Kilometers
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New research suggests the initial spread of the coronavirus, which caused the COVID-19 pandemic, is linked to the wildlife trade across important distances. The findings, published in the journal Cell, also challenge the theory that the virus originated from a laboratory leak.
Genetic Analysis Points to Animal Trade
according to genetic analyses, the SARS-CoV-2 virus likely reached the area where the outbreak began in China through the trade of wild animals. Researchers posit a similar pattern for the SARS-CoV-1 pathogen, which caused the SARS epidemic in 2002-2003. The team’s report in Cell indicates that the limited mobility of the animals, combined with the estimated age of the virus, makes it improbable that direct ancestors of SARS-CoV-1 and SARS-CoV-2 reached their respective outbreak locations solely through bat migration.
The precise origin of the virus that triggered the COVID-19 pandemic in Wuhan, China, in 2020 remains a subject of debate. Speculation was fueled by reports suggesting a potential leak from a Chinese laboratory.
long-Term Impact of Pandemic
The pandemic’s effects continue to be felt.estimates indicate a doubling of chronic fatigue syndrome (ME/CFS) cases in Germany, affecting approximately 600,000 individuals.The ME/CFS Research Foundation estimates the economic impact could exceed 60 billion euros annually, based on a recent modeling study. ME/CFS can manifest as a long-term complication following various viral infections, including “Long COVID.”
Tracing the virus’s Origins
The Cell study examines the genetic lineage of the virus. researchers found that the closest detectable ancestors of SARS-CoV-1 and SARS-CoV-2 existed less than a decade before they jumped to humans. Jonathan Pekar, formerly of the San Diego School of Medicine at the University of California and now at the University of Edinburgh, stated that the original SARS-CoV-1 circulated in western china one to two years before the SARS outbreak in Guangdong province in south-central China. Similarly, SARS-CoV-2 circulated in western China or northern Laos five to seven years before the COVID-19 outbreak in Wuhan.
distance and Wildlife Trade
The researchers argue that the distance between western China or northern Laos and Wuhan – up to 2,700 kilometers – is too great for the virus to have spread naturally via it’s primary host, the horseshoe bat. They suggest it is more likely that wildlife traders transported the virus via intermediate hosts. According to the Cell report, the wildlife trade played a crucial role in the emergence of COVID-19 in humans.
Earlier research suggested that masked palm civets or raccoon dogs carried the precursor to SARS-CoV-1 from Yunnan province in western China to Guangdong province, a distance of over 1,000 kilometers. these animals are frequently traded for their fur and meat.
Similar Patterns Observed
Michael Worobey, a co-author from the University of Arizona, noted the current analysis provides strong evidence that a similar process occured with SARS-CoV-2. “At SARS-CoV-2 we see exactly the same pattern,” he said.
The findings challenge the hypothesis that while SARS-CoV-1 originated naturally, SARS-CoV-2 may have resulted from a laboratory leak. Joel Wertheim from the University of California explained that the distance between Wuhan and the bat virus reservoir was considered too great for a natural animal transmission origin.”This work shows that this is not unusual and the appearance of Sars-Cov-1 is very similar in 2002.” SARS-CoV-1 caused a global epidemic with approximately 800 deaths and is now considered extinct.
Sarbecoviruses Research
Following the emergence of SARS-CoV-1 in 2002 and SARS-CoV-2 in 2019, researchers have increasingly studied circulating sarbecoviruses in horseshoe bats. they typically use the entire genome sequence for comparisons. However, the viruses undergo frequent recombinations within their bat hosts, exchanging genetic material, which complicates the understanding of their evolution.
Wertheim explained that when two different viruses infect the same bat, the resulting virus can be a mixture of parts from both. This recombination makes it tough to understand the evolution of these viruses because different parts of the genome have different evolutionary histories. Consequently, the progress of a specific pathogen cannot be easily understood through conventional genetic comparison.
The researchers addressed this issue by identifying non-recombining regions of the available 250 genomes and using only those regions to trace the evolutionary history. The results indicate that SARS-CoV-like viruses have been circulating in western China and Southeast Asia for thousands of years, moving through the landscape at a similar pace as their horseshoe bat hosts.
The study notes that these bats typically have small distribution areas,averaging two to three square kilometers of movement per night. They exhibit limited migration and, consequently, a limited capacity for spreading viruses over long distances.
Limitations of the Study
The researchers acknowledge that significant regional gaps in the recorded sequences could skew the conclusions regarding the precise locations of SARS-CoV-1 and SARS-CoV-2 origins. They also state that even with increased sampling, finding the direct ancestor of the two viruses may not be possible.
COVID-19 Origins: Q&A on the Wildlife Trade Link
What does the new research suggest about the origin of COVID-19?
New research suggests the initial spread of the coronavirus, which caused the COVID-19 pandemic, is linked to the wildlife trade across notable distances.The findings challenge the theory that the virus originated from a laboratory leak.
How does genetic analysis point to the role of wildlife trade?
Genetic analyses indicate that the SARS-CoV-2 virus likely reached the area where the outbreak began in China through the trade of wild animals. Researchers posit a similar pattern for the SARS-CoV-1 pathogen, which caused the SARS epidemic in 2002-2